On Wed, 22 Oct 2025 12:32:41 +0200 Ketil Johnsen <[email protected]> wrote:
> There is a race between panthor_device_unplug() and > panthor_device_suspend() which can lead to IRQ handlers running on a > powered down GPU. This is how it can happen: > - unplug routine calls drm_dev_unplug() > - panthor_device_suspend() can now execute, and will skip a lot of > important work because the device is currently marked as unplugged. > - IRQs will remain active in this case and IRQ handlers can therefore > try to access a powered down GPU. > > The fix is simply to take the PM ref in panthor_device_unplug() a > little bit earlier, before drm_dev_unplug(). > > Signed-off-by: Ketil Johnsen <[email protected]> > Fixes: 5fe909cae118a ("drm/panthor: Add the device logical block") Reviewed-by: Boris Brezillon <[email protected]> > --- > drivers/gpu/drm/panthor/panthor_device.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_device.c > b/drivers/gpu/drm/panthor/panthor_device.c > index 81df49880bd87..962a10e00848e 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.c > +++ b/drivers/gpu/drm/panthor/panthor_device.c > @@ -83,6 +83,8 @@ void panthor_device_unplug(struct panthor_device *ptdev) > return; > } > > + drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0); > + > /* Call drm_dev_unplug() so any access to HW blocks happening after > * that point get rejected. > */ > @@ -93,8 +95,6 @@ void panthor_device_unplug(struct panthor_device *ptdev) > */ > mutex_unlock(&ptdev->unplug.lock); > > - drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0); > - > /* Now, try to cleanly shutdown the GPU before the device resources > * get reclaimed. > */
